“Frankly, Jeremy, the only way I can think of is to accept a little risk and go through it really fast. At 2/3 lightspeed, for instance, you and your two-meter-tall suit would transit that zero-thickness boundary in about 10 nanoseconds. In such a short time your atoms won’t get much out of position before the electromagnetic fields that hold your molecules together kick back in again.”

“OK, I’ve passed through. On to the Firewall … but what is it?”

“An object of contention, for one thing. A lot of physicists don’t believe it exists, but some claim there’s evidence for it in the 2015 LIGO observations. It was proposed a few years ago as a way out of some paradoxes.”

“Ooo, Paradoxes — loverly. What’re the paradoxes then?”

“Collisions between some of the fundamental principles of Physics-As-We-Know-It. One goes back to the Greeks — the idea that the same thing can’t be in two places at once.”

“Tell me about it. Here’s your desserts.”

“Thanks, Eddie. The place keeping you busy, eh?”

“Oh, yeah. Gotta be in the kitchen, gotta be runnin’ tables, all the time.”

“I could do wait-staff, Mr G. I’m thinking of dropping track anyway, Mr Moire, 5K’s don’t have much in common with base running which is what I care about. How about I show up for work on Monday, Mr G?”

“Kid calls me ‘Mr’ — already I like him. You’re on, Jeremy.”

“Woo-hoo! So what’s the link between the Firewall and the Greeks?”

“Link is the right word, though the technical term is entanglement. If you create two particles in a single event they seem to be linked together in a way that really bothered Einstein.”

“For example?”
“Polarizing sunglasses. They depend on a light wave’s crosswise electric field running either up-and-down or side-to-side. Light bouncing off water or road surface is predominately side-to-side polarized, so sunglasses are designed to block that kind. Imagine doing an experiment that creates a pair of photons named Lucy and Ethel. Because of how the experiment is set up, the two must have complementary polarizations. You confront Lucy with a side-to-side filter. That photon gets through, therefore Ethel should be blocked by a side-to-side filter but should go through an up-and-down filter. That’s what happens, no surprise. But suppose your test let Lucy pass an up-and-down filter. Ethel would pass a side-to-side filter.”

“But Sy, isn’t that because each photon has a specific polarization?”

“Yeah, Jennie, but here’s the weird part — they don’t. Suppose you confront Lucy with a filter set at some random angle. There’s only the one photon, no half-way passing, so either it passes or it doesn’t. Whenever Lucy chooses to pass, Ethel usually passes a filter perpendicular to that one. It’s like Ethel hears from Lucy what the deal was — and with zero delay, no matter how far away the second test is executed. It’s as though Lucy and Ethel are a single particle that occupies two different locations. In fact, that’s exactly how quantum mechanics models the situation. Quite contrary to the Greeks’ thinking.”

“You said that Einstein didn’t like entanglement, either. How come?”

“Einstein published the original entanglement mathematics in the 30s as a counterexample against Bohr’s quantum mechanics. The root of his relativity theories is that the speed of light is a universal speed limit. If nothing can go faster than light, instantaneous effects like this can’t happen. Unfortunately, recent experiments proved him wrong. Somehow, both Relativity and Quantum Mechanics are right, even though they seem to be incompatible.”

“And this collision is why there’s a problem with black hole evaporation?”